On Wed, Jun 05, 2019 at 04:04:05PM +0200, Sebastian Andrzej Siewior wrote: > On 2019-06-04 11:53:58 [-0700], Eric Biggers wrote: > > On latest Linus' tree I'm getting a crash in a 32-bit Wine process. > > > > I bisected it to the following commit: > > > > commit 39388e80f9b0c3788bfb6efe3054bdce0c3ead45 > > Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > > Date: Wed Apr 3 18:41:35 2019 +0200 > > > > x86/fpu: Don't save fxregs for ia32 frames in copy_fpstate_to_sigframe() > > > > Reverting the commit by applying the following diff makes the problem go away. > > This looked like a merge artifact and it has been confirmed as such. Now > you say that this was a needed piece of code. Interesting. > Is that wine process/testcase something you can share? I will try to > take a closer look. > > Sebastian As I said, the commit looks broken to me. save_fsave_header() reads from tsk->thread.fpu.state.fxsave, which due to that commit isn't being updated with the latest registers. Am I missing something? Note the comment you deleted: /* Update the thread's fxstate to save the fsave header. */ My test case was "run some Win32 game for a few minutes and see if it crashes" so it's not really sharable, sorry. But I expect it would be possible to write a minimal test case, where a 32-bit process sends a signal to itself and checks whether the i387 floating point stuff gets restored correctly afterwards. - Eric
